It is known to provide communications networks having path computation elements (PCE) for computing which path resources (for example links, nodes, frequency or time slots) to select for a new path through the network. A PCE has been defined as an entity (component, application, or network node) that is capable of computing a network path or route based on a network graph and applying computational constraints. A Path Computation Client (PCC) is any entity which requests a path computation to be performed by the PCE. The PCC and PCE in a typical example communicate through the PCE communication Protocol (PCEP). PCEP operations have been defined to enable effective PCE-based path computations and, in turn, the effective use of network resources. A PCE-based architecture is described in Internet Engineering Task Force (IETF) document RFC 4655 and the PCE communication Protocol is described in RFC 4657.
WO2013188779 shows a stateful path computation element (PCE) in a computer network which receives one or more path computation requests (PCReqs), and records a time of each PCReq and the corresponding requested bandwidth. Based on this information, the PCE may determine a traffic profile of the computer network, and may augment a traffic engineering database (TED) with requested bandwidth according to time based on the traffic profile. As such, prior to a particular time, the PCE may determine placement of tunnels within the traffic profile for the particular time.